rculfhash: document flags

[urcu.git] / rculfhash.c

diff --git a/rculfhash.c b/rculfhash.c
index 55f56ceb6bc54a248032d3e2ce94e2db1bfeb82b..e8147178ada51bc333c27237ac806311c8bc08a0 100644 (file)
--- a/rculfhash.c
+++ b/rculfhash.c
@@ -53,6 +53,11 @@
 #define max(a, b)      ((a) > (b) ? (a) : (b))
 #endif
 
+/*
+ * The removed flag needs to be updated atomically with the pointer.
+ * The dummy flag does not require to be updated atomically with the
+ * pointer, but it is added as a pointer low bit flag to save space.
+ */
 #define REMOVED_FLAG           (1UL << 0)
 #define DUMMY_FLAG             (1UL << 1)
 #define FLAGS_MASK             ((1UL << 2) - 1)